The invention relates to an energy-absorbing deformation profile for a motor vehicle, particularly in the case of a knee protection device for the underside of a center console area.
The device has at least two hollow profile sections with a honeycomb-type design which adjoin one another along a common deformation axis and has a linkage profile section for fastening the deformation profile on a member part of a vehicle body support structure, particularly on a center console cross member.
An energy-absorbing deformation profile of this generic type, known for example, from the journal Automotive Engineering, January 1997 Volume, Page 139, is used in a knee protection device for an underside of a center console area of a passenger car. The energy-absorbing deformation profile is made of aluminum and has three hollow profile sections which carry out the energy-absorbing deformation, and which each have a honeycomb-type design. The hollow profile sections are arranged behind one another in the deformation direction. In addition, the deformation profile has a linkage profile section which has a high stiffness and is used to fasten the deformation profile on a center console cross member of the vehicle body support structure. Because of the stiff linkage profile section, further energy absorption by the knee protection device is no longer possible when the three honeycomb-type hollow profile sections have been pressed together to form a block.
It is an object of the present invention to provide an energy-absorbing deformation profile of the initially mentioned type, which has an increased energy-absorbing capability in comparison to the prior art.
This and other objects and advantages are achieved by the energy absorbing deformation profile according to the invention, in which the linkage profile section has an energy-absorbingly deformable design. As the result of the additional energy absorbing effect of the linkage profile section, a supplementary deformation path is provided which increases the energy absorption capacity of the whole deformation profile. This additional deformation path does not exist in the prior art, in which the linkage profile section has a stiff and inflexible design. In addition, the enlarged deformation path prevents a sudden rise of force after the utilization of the whole deformation path of the hollow profile section because of the occurring block formation.
As a further development of the invention, the hollow profile sections are arranged to be offset relative to the linkage profile section, such that the deformation axis extends at a distance from the member part of the vehicle body support structure. As the result of this further feature, the direction of the effect of the energy-absorbing deformation of the hollow profile sections is applied at a distance from the member part, so that a corresponding moment is introduced into the member part. An additional deformation path laterally adjacent to the member part can therefore be utilized, since the deformation direction extends past the member part.
In a further embodiment of the invention, the energy-absorbing deformation of the linkage profile section is designed such that a force level necessary for deformation of the linkage profile section is higher than a force level required for deformation of the honeycomb-type hollow profile sections. This ensures that, in the event of a deformation, the honeycomb-type hollow profile sections are deformed first, followed by the linkage profile section. Thus, in the event of a corresponding impact stress on the motor vehicle, the deformation path of the honeycomb-type hollow profile sections will be utilized first.
As a further feature of the invention, the linkage profile section is provided with a parallelogram-type effective cross-section. This ensures that, also after a completed compression for the block formation, the hollow profile sections do not swivel about the member part, but carry out a further movement in the direction of the deformation force. As the result, a largely rectangular characteristic force-path curve can be achieved in the event of dynamic stress.
As a further feature of the invention, the linkage profile section has an angular contact area which partially encloses a square cross member. As a result, a secure fastening of the linkage profile section (and thus of the deformation profile on the cross member) is achieved, without any reduction of the available deformation path.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.